[faq] Add section on C++ wrapping, pickling, and parameter limits
[faq] Add section on C++ wrapping, pickling, and parameter limits

ipashchenko/emcee,willvousden/emcee,linan7788626/emcee,johnbachman/emcee,joezuntz/emcee,jellis18/emcee3,johnbachman/emcee,drphilmarshall/emcee,ga7g08/emcee,pkgw/emcee,dfm/emcee,willvousden/emcee,farr/emcee,dfm/emcee3,elkingtonmcb/emcee,dfm/emcee,ipashchenko/emcee-x